Hydrodynamic coupling devices



March 13, 1962 R. c. ZEIDLER HYDRODYNAMIC COUPLING DEVICES 2Sheets-Sheet 1 Filed May 20. 1955 fnverffar Fain/ 01d CZez'ciZer March13, 1962 R. c. ZEIDLER HYDRODYNAMIC COUPLING DEVICES 2 Sheets-Sheet 2Filed May 20. 1955 fie zLH/LOZOZ C Zelciler" Illinois Filed May 20,1955, Ser. No. 509,718 4 Uranus. (Cl. 103111) This invention relates tohydrodynamic coupling devices and more particularly to housings of suchdevices providing a toroidal fluid circuit in which are disposedimpeller blades and turbine blades, the housing comprising twosubstantially semi-toroidal shells with the impeller blades beingpreferably connected to one of the shells of the housing, the turbineblades being connected to a separate coupling member relativelyrotatable to the housing.

Hydraulic coupling devices such as fluid couplings and torque convertershave in the past been formed with two substantially semi-toroidalshells, the shells being respectively formed of aluminum and steel, orboth shells being formed of steel. In assemblying aluminum and steelshells, it has been the conventional practice to connect the Shells attheir radially outer peripheries with bolts or screw-threaded devices toconnect the aluminum shell to the steel shell in view of the inabilityof welding, or otherwise connecting, the aluminum shell to the steelshell. This is an expensive operation in view of the necessity offorming screw threads in at least one of the shells to receive thebolts, and providing openings in the other shell to receive the bolts tobe threaded into the first-mentioned shell; or alternatively providing aseparate screw-threaded ring engaging one of the shells and threads onthe other shell in order to assemble the shells together. In eithercase, the connection of an aluminum shell to a steel shell involves amultitude of expensive operations, including hand operations, to providethe satisfactory assembly of the shells. It has been found simpler andinexpensive to connect two steel shells together to form the housing, bytelescoping the two steel shells at their outer peripheries, andproviding a continuous weld between the edge of the outer telescopingmember and the outer surface of the inner telescoped member to insure asatisfactory connection between the two shells, and to prevent thepossibility of any leakage of the fluid from the housing provided byconnected shells.

Inconventional automotive transmission practice, the hydrodynamiccoupling device embodying the housing has one of the shells thereofusually connected to the crankshaft of the engine, either directly or bya drive plate, and the turbine member of the fluid coupling or torqueconverter is connected to the transmission input shaft, the crankshaftand the transmission being disposed on a common axis and terminating atfixed spaced points on the axis for reception of the hydrodynamiccoupling device therebetween and connection to the shafts. Thus, it isnecessary that the axial dimension of the device be consistentlymaintained to insure the proper location between the engine andtransmission and comiection to the engine crankshaft and thetransmission input shaft. It has been found by connecting the two shellsforming the fluid-containing housing, by a continuous weld, reduction inthe diameter of the housing occurs adjacent to the weld. This reductionin diameter extends a short distance on either side of the weld and iscaused by the fact that, during the welding operation, the twotelescoped shells adjacent to the weld become highly heated, so thatconsequently, upon cooling, the shrinkage produces a reduction in thediameter. This reduction in the diameter, and particularly where theshell of the housing, connected to the engine crankshaft, is shallowcauses Q 3,a2t,735 163g Patented Mar. 1 1962 this shell to bulge towardthe engine crankshaft and destroys the required accurate axial dimensionof the hydrodynamic coupling device for location between and assemblywith the engine crankshaft and the transmission input shaft. Thisundesirable factor has provided an obstacle, in many cases, to utilizinga housing formed of two shells provided with a continuous weld, asdescribed, in the assembly of the two shells at the factory, and acondition which is considerably aggravated in the service field wherethe two shells of the housing must be disconnected and then reweldedafter the necessary repairs have been made to the hydrodynamic couplingdevice.

It is the object of the present invention to provide an improvedstructure and assemblies of two shells of a hydrodynamic coupling devicehousing in which the two shells of the housing may be assembled in aready and facile manner, during the assembly operation withoutdeformation or distortions of the shells and consequent changes in theaxial and diametrical dimensions of the housing.

it is another object of the invention to provide an improved structureand assembly of housings for hydrodynamic coupling devices in which thetwo telescoped outer portions of the shells of the housing are connectedto each other while maintaining the original shape of the shells andwithin the predetermined space limits required for assembly of thedevices between the engine and the transmission of an automotivevehicle.

Another object of the invention is to provide a new and improvedstructure and assembly of two shells of a housing of a hydrodynamiccoupling device, having telescoping outer peripheries connected to eachother by welding, or by interlocking portions thereof, to provide aconnection insuring the two shells from disassembly under thecombination of hydraulic static pressure and centrifugal forceencountered in the operation of the hydrodynamic coupling devices.

The invention consists of the novel constructions, arrangements, devicesand methods of assembly to be hereinafter described and claimed forcarrying out the abovestated objects, and such other objects as willappear from the following description of certain preferred embodimentsillustrated in the accompanying drawings, wherein:

FIG. 1 is a fragmentary side elevation, partly in section of a hydraulictorque converter showing a preferred embodiment of the invention;

FIG. 2 is a fragmentary elevation view, taken on line 22 of FIG. 1 andlooking in direction of the arrows;

FIG. 3 is a fragmentary sectional view of another embodiment of theinvention and illustrating a differ out form of connection between thetwo shells of the housing;

PEG. 4 is a top plan view, partly in section, of the housing structureshown in FIG. 3 and as indicated by the plane 4-4 of FIG. 3;

FIG. 5 is another embodiment of the invention illustrating a differenttype of connection of the two shells of the housing;

FIG. 6 is similar to FIG. 5, illustrating a different location of theseal ring;

FIG. 7 is a sectional view illustrating another embodiment of theinvention and illustrating a further type of connection of the twoshells of the housing;

FIG. 8 is top plan view of the connection shown in FIG. 7, as indicatedby the plane 88 of FIG. 7;

FIG. 9 is a view similar to FIG. 7, but illustrating the disposition ofthe shells prior to connecting the shells by a final assembly operation.

FIG. 10 is a View similar to FIG. 7, illustrating a dif- 3 ferentlocation of the seal ring between the two shells;

FIG. 11 is a sectional view illustrating another embodiment of theinvention;

FIG. 12 is a sectional view illustrating a further embodiment of theinvention; and

FIG. 13 is a fragmentary sectional view of a housing having its twoshells connected together in accordance with prior art practice.

Referring now to the drawings and first describing the hydrodynamiccoupling device shown as a hydraulic torque converter in FIG. 1, theconverter comprises a varied driving element or impeller or pump 10, avaried driven element or turbine 11, and a vaned reaction element orstator 12, the pump functioning to impart energy to a body of liquid inthe torque converter, the turbine receiving energy from the liquid, andthe stator being held from rotation and acting to change the directionof the flow of the liquid so that the device functions to multiplytorque.

A one-way brake 13 of the sprag type is disposed between the stator 12and a stationary cylindrical portion 14 of a transmission casing, theone-way brake being operative to prevent rotation of the stator in onedirection during the torque multiplication stages of the converter,while permitting rotation of the stator in the opposite direction atwhat is commonly termed the coupling point of the torque converter. Thevanes of the pump, turbine and stator may be of the type illustrated anddescribed in the U.S. Patent 2,663,149, issued December 22', 1953.

The pump 10 is connected to an engine (not shown) having a shaft 15driven thereby and provided with a flange 16 connected by bolts 17 to adrive member 18 connected to the pump 10* for driving the pump. As seenin FIG. 1, the bolts 17 :may have their heads spot-welded as at 19 tothe drive plate with the shank of the bolts extending through openingsin the engine shaft flange 16 and being secured thereto by nuts 20. Theturbine 11 is provided with a hub 21 splined to a driven shaft 22 whichmay be the input shaft of a gear set of a transmission. The impeller 10is provided with a hub rotatably supported upon the cylindrical portion14 of the transmission casing.

The hydraulic torque converter is designed to be filled with a liquidfor the transmission of torque from the impeller 10, rotated by theengine, to the turbine 11 connected to the driven shaft 22. It will beseen from an inspection of FIG. 1 that the impeller lit is provided witha hollow substantially semi-toroidal shell 2-3 having its radially outerperiphery defined by an annular portion or cylindrical flange 24, vanes25 being disposed between and connected to a core ring 26 and the shell23. The drive plate 18 is a hollow shell formed with a substantiallysemi-toroidal portion provided with a radially outer annular peripheralport-ion defined by a flange 27 reversely bent relative to thesemi-toroidal portion thereof to extend axially through a radial planeintersecting the semitoroidal portion thereof. The flange 2'7 isradially inwardly of the cylindrical flange 24 of the shell 23, andextends in the same direction of the axis of rotation A-A of the torqueconverter as the flange 24 for telescoping relation with the flange 24-.The semi-toroidal portions of the shells 18 and 23 thus define a housingforming a fluid chamber for containing fluid in the fluid torqueconverter, with the engaged portions of the flanges projecting axiallyaway from the housing, The telescoped flange 27 of the shell 18 and thetelescoping flange 2.4 of the impeller shell 23 are provided withshoulders 28 and 2 respectively having radial surfaces cooperating toengage each other to locate the shells 1B and 23 in a predeterminedaxially spaced relation with the circumferential extending edges of theflanges disposed in a common radial plane. The flange 27 of the shell 13is provided with an annular groove 30 receiving a ring of synthetic ornatural rubber, the ring being compressed between the flanges 24 and 27and providing a seal to prevent the flow of liquid between thetelescoped flanges and from the converter under centrifugal pressure orhydraulic static pressure forces in the housing during operation of theconverter.

As the circumferentially extending edges of the flanges 27 and 24 are inradial alignment, the edges may be secured together to hold the shellsin assembly by a plurality of circumferentially spaced spot welds 31extending between and connecting the edges by puddle or track welding,the welds thereby becoming integral portions of the shells to hold thetwo shells in assembly and from slipping apart under the combination ofhydraulic static pressure and centrifugal force. The welding operationtakes place quickly and a minimum amount of heat is generated, and, dueto the fact that only a small amount of welding is applied, very littledistortion, if any, of the welded parts occurs. The shells 1.8 and 23are formed of sheet steel stampings having their outer annular flanges24 and 27, respectively, machined accurately to permit a close slip fit,with the shoulders 28 and 29 in both shells permitting the shells toengage a predetermined amount so that the overall height of the assemblyis maintained. It will be apparent that the small amount of weldingaccomplished quickly at localized circumferentially spaced portions ofthe ends. of the flanges 24 and 27, together with the fact that the weldoccurs at a substantial distance from the semi-toroidal portions of theshells, eliminates the possibility of any distortion of the shellsoccurring to reduce the diameter of the assembly or to lengthen theaxial dimension of the torque converter.

FIG. 13 illustrates a conventional housing of a hydraulic torqueconverter comprising two shells I and P having telescoping flanges P 1with a continuous weld W between the edge of the flange P and the outersurface of the flange 1,. It has been found, in welding the two shellstogether in the manner described to form the torque converter housing,objectionable distortion of the shells occurs as there is a reduction indiameter extending a short distance on either side of the weld causingthe shell P to be distorted and to increase its axial dimension asindicated in dotted lines in FIG. 13. This reduction on diameter of theshells P and I of the converter housing is caused by the fact that,during the welding operation, the two shells have their portions,adjacent to the weld, highly heated and, consequently, upon cooling theshrinkage produces a reduction in diameter of as much as .025 inch withthe attendant result that the housing is distorted in an axial dimensionwhich renders it incapable of being fitted within or located in thepredetermined axial space alloted to it between an engine and atransmission and connection to the engine crankshaft and transmissioninput shaft, with the result that the torque converter may not besuitable for installation in the limited space provided for it betweenthe engine and transmission by automobile manufacturers.

It will be seen that, in the assembly of the shells 18 and 23 of thehousing in FIG. 1, the remoteness of the plurality of welds to thesemi-toroidal portions of the shells, together with the very limited andquick application of heat at circumferentially spaced points on thealigned edges of the flanges of the shells will prevent any possibilityof the shells 18 and 23 being distorted during the assembly operation.

FIGS. 3 and 4 illustrate another embodiment of the invention affording aconnection between two shells 18a and 23a, of a torque converterhousing, the shell 18a and the shell 23a having semi-toroidal portions,telescoping radially outer annular portions or flanges 27a and 24aextending in the same axial direction, and the shell flanges havingradially extending surfaces provided by abutting shoulders 28a and 29a,similar to the features illustrated in FIG. 1. A resilient rubber ring3011 is disposed in a groove in the flange 27a for engagement with theflange 24a of the shell 23a. In this embodiment of the invention, thecircular edge of the annular flange 27a of the shell 18a is providedwith a plurality of circumferentially spaced notches 32 as shown in FIG.4, and the outer terminal edge of the axially extending flange 24a isrolled or spun over the terminal edge of the flange 27a to provide aradially inwardly directed continuous lip to prevent axial movement ofthe shells away from each other, portions of the lip forming tongues 33received within the notches 32 in the edge of the flange 27a to preventrelative rotation of the shells 18a and 23a about the axis of the torqueconverter. This assembly of the two shells of the housing of the torqueconverter cannot, in any way, cause distortion of the two shells as thespinning or rolling operation is only effective upon the thin outermarginal edge of the shell 23a in engaging the outer edge of the shell18a and disposing the tongues 33 in the notches 32. It will be notedthat the radially extending surfaces on the abutting shoulders 28a and29a form a stop for preventing relative axial movement of the shellsduring the spinning or rolling operation.

FIG. 5 illustrates another embodiment of the invention in which twoopposed hollow shells 18b and 2312 have radially outer annular portionsor flanges each formed by angularly related parts extending respectivelyin axial and radial directions. The axially extending parts 34 and 35are in telescoped relation and the radially outwardly extending parts 36and 37 are engaged with each other as clearly shown in FIG. 5, theradially extending part 37 of the flange of the shell 18b being bent atright angles to the axially extending part of the flange of the shelland the radially extending part 36 of the flange of the shell 231; alsobeing bent at right angles to the axially extending part 34 of theflange of the shell. A circular ring 38 of natural or synthetic rubheris positioned between and at the juncture of the angularly disposedparts 35 and 37 of the flange of the shell 18b and the angularlydisposed parts 34 and 36 of the flange of the shell 23b to provide aseal to prevent the escape of fluid from the housing formed by theshells 18b and 23b. In the assembly of the shells, the axially extendingparts 34 and 35 are disposed in telescoping relation to effectengagement of the outwardly directed parts 36 and 37 to thereby compressthe rubber ring 38 between the flanges of the shell 18!) and the shell23b. The radially outer edges of the flanges are each radially disposedthe same distance from the axis of the torque converter so that aplurality of welds 39, provided thereon by puddle or tack welding atcircumferentially spaced areas thereof, will securely hold the shells18b and 23b connected to each other against relative rotation andmovement of the shells 13b and 23b away from each in axial direction,the abutting parts 36 and 37 of the flanges preventing axial movement ofthe shells 18b and 23b toward each other.

The embodiment of the invention illustrated in FIG. 6 is similar to thatillustrated in FIG. 5 with the exception that the telescoped radiallyinner axially extending part 40 of the flange of the shell 18c isprovided with an annular groove 41 receiving an O ring of natural orsynthetic rubber compressed between the telescoping parts of the flangesof the shells 13c and 23b to prevent any possibility of leakage of thefluid from the housing defined by the shells.

In the embodiments of the invention illustrated in FIGS. 5 and 6, thewelding operation takes place quickly and with a minimum amount of heatbeing generated so that with the small amount of welding applied verylittle distortion, if any, occurs in the parts.

FIGS. 7, 8 and 9 illustrate another embodiment of the invention forassemblying two opposed hollow shells 43 and 44 having substantiallysemi-toroidal portions, as shown in FIG. 1. The shell 43 is preferablyformed as an aluminum casting provided with a radially outer annularportion or flange 45 having an annular rib 46 projecting radiallyoutwardly from the outer cylindrical surface thereof at itscircumferentially extending edge 47. The shell 44 is provided with aradially outer portion or axially extending flange 48 in telescopingrelation to the flange 45 and engaging rib 46. As seen more particularlyin FIG. 8, the rib 46 is provided with a plurality of circumferentiallyspaced notches or recesses 49 in the radially extending surface at oneside thereof, for receiving a plurality of tongues 51 entering into thenotches 49 during the spinning or rolling operation of thecircumferentially extending end of the flange 48 to provide a radiallyinwardly extending annular lip 52 engaging the side 50 of the rib 46 toprevent relative axial movement of the shell 44 and the shell 43 awayfrom each other and to prevent relative rotation of the shells. As seenin FIG. 7, the shell 44 is provided with a shoulder 53 having an axiallyextending surface engaging the radially inner surface of the cylindricalflange 45 of the shell 43. It will be seen that the abutment of the endof the flange 45 of the shell 43 with the radially extending portion ofthe shell 44, in cooperation with the lip 51 engaged with the rib 46,prevents relative axial movement of the two shells. A ring 54 of naturalor synthetic rubber is disposed between the flanges 45 and 48 at thejuncture of the radially and axially extending portions of the flange 48and engages an inclined surface 54a on the end of the flange 45 and thering is thereby compressed between the two shells to prevent leakage offluid between the flanges and from the housing. The formation of the rib46 on the shell 43 is related to the flange 48 of the shell 44 so thatthe abutment of the end of the flange 45 of the shell 43 against theshell 44 positions the end of the flange 48 to be moved radiallyinwardly by a rolling or die operation from the position shown in FIG. 7and over the side 50 of the rib 46 to engage the same and to enter thenotches 49 in the rib 46, as shown in FIGS. 8 and 9.

The embodiment of the invention illustrated in FIG. 10 is similar tothat illustrated in FIGS. 7, 8 and 9 with the exception that thecylindrical portion 55a of the cast aluminum shell 55 is provided with arib 56 having an annular groove 57 therein for receiving an O ring 57acompressed between the flange 48 of the shell 44 and the flange 55a ofthe shell 55.

In each of the embodiments of the invention illustrated in FIGS. 7, 8and 9 and FIG. 10, the shoulder 53 on the shell 44 is essential toprevent the shell 43 or 45 from collapsing inwardly during the rollingor di operation flanging over the end of the flange 48 of the shell 44to form the lip 52. In each of these assembly operations, the shell 44and the shell 43 or 45 are required to be pressed together so that theedge 47 of the shell 43 or 45 butts firmly against the shell 44 and theseal ring is compressed a desired amount to prevent leakage of fluid. Itwill be apparent that, in the absence of the shoulder 53 on the shell44, the shell 43 or 45 might be distorted inwardly during the formingconnecting operation, which would relieve the pressure on the seal ringand possibly permit leakage of the fluid from the housing.

It will be apparent from an inspection. of the two embodimentsillustrated in FIGS. 7, 8 and 9 and in FIG. 10, that the two shells areheld tightly secured together against relative axial movement andrelative rotary movement by the assembly operations described.

In the embodiment of the invention of FIG. 11, another form ofconnection is illustrated between a drive plate 58 and impeller casing59 providing two opposed shells having substantially semi-toroidalportions as shown in FIG. 1. The shell 58 has an outer circumferentiallyextending annular flange 60 surrounding a radially extending flange 61of the shell 59. The flange 60 forms a reduced end portion of the shell58 to provide a shoulder 62 defining a pocket with the flange 61, theshoulder abutting the radially extending portion 63 of an annular sheetmetal stamping or ring 64 of L-section extending within the pocket, theaxially extending portion 65 of the ring having its edge engaging theside of the flange 61 of the shell 59, and the edge of the ring portion63 being seated against the circumferentially extending inner surface ofthe flange 60. The ring 64 thus serves to space the shells 58 and 59 sothat, in the assembly operation, the end of the flange 60 extendsaxially beyond the flange 61. A in the embodiment illustrated in FIGS.7-9, inclusive, the end of the flange 60 is formed over by a rolling ordie operation to form a lip 66 in engagement with the side of the flange61 to secure the shells together against axial movement away from eachother and with portions of the lip entering notches 67 in the side ofthe flange 61 to prevent relative rotation of the shells. A seal ring 68of compressible material, such as rubber, and which may be an O ring, isreceived within the L-shaped ring 64-, as shown, is compressed betweenthe ring 64 and the flanges 60 and 61 to prevent leakage of fluid fromthe connected shells. In the assembly operation, when the two shells arepressed together to compress and load the rubber seal, the rubber sealbottoms against the ring 64 and through it to the shoulder 62, and whilethe parts are held in this position, the end of the flange 60 is formedover to lock the two shells together.

Referring to FIG. 12 showing another type of connection' between twoshells 69 and 70, the shell 69 has a circumferentially extending annularflange 71 in telescoping relation to a flange 72 of the shell 70. Theend of the flange 72 is machined at its outer diameter to provide areduced portion providing a shoulder 74 abutting the edge of the flange71 to position the shells in predetermined axial relation to each other.The end of the flange 71 is also of reduced diameter to provide ashoulder 75 defining a pocket the end of the flange 72, the shoulder 75abutting the side of a radially extending portion 76 of an annular sheetmetal stamping or ring 77 of L-section. The ring 77 has its axiallyextending portion 78 extending toward and disposed radially inwardly ofthe end of the flange 72. Disposed within and engaging the ring 77 is arubber seal ring 79 in engagement with the ring 77, the end of theflange 72 and the inner surface of the reduced portion of the flange 72.

In the assembly of the shells, the shells are held tightly together withthe shoulder 75 of the flange 71 and the end of the flange 72compressing the seal ring 79 a predetermined amount while a weldingoperation is performed to provide a plurality of circumferentiallyspaced welds 80 between the flanges 71 and 72 as shown. The edge of theflange 71 may be beveled and recesses formed therein and in the flange71 to provide sufliciently large adjacent areas to insure satisfactorywelds 80 between the flanges to securely connect the shells to eachother.

The connections of the two shells illustrated in FIGS. 1 and 2, and 6,and 12 are particularly adaptable for servicing by garages and the like.In FIGS. 1 and 2, 5 and 6, the two shells can be easily disassembled byremoving the welds by machining about .050 inch of the edges of thetelescoping ends of the shells, and in FIG. 11, the welds may be removedby machining the welds from the shells and in each case, a new seal ringis then installed. Since no distortion occurred originally in thewelding operation, the shells can then be quickly telescoped again toabut their original shoulders or engaging parts and thereafter thewelding operation to connect the shells can be done with equipmentavailable at any service station or garage. The connections and assemblyof the shells illustrated in FIGS. 3 and 4, 7, 8 and 9, FIG. 10, andFIG. 11 could be serviced in the field by service stations and garagesby reversely rolling the spun-over edge of the telescoping shellallowing the two shells to be readily disassembled for servicing of thetorque converter, including replacement of the seal ring, and thereafterthe two shells may be telescoped and the edge of the telescoping shellagain either spun or rolled over the:

telescoped shell to connect the shells together.

It will be apparent from the foregoing description that I have providedimproved structures and assemblies of shells of fluid-containinghousings of hydrodynamic con-- pling devices, which may be of the fluidcoupling or hydraulic torque converter types, in which two shells may bereadily assembled and secured together in a manner retaining theoriginal shapes of the shells to provide housings with uniform axial andradial dimensions to satisfy the limited space requirements bothdiametrically and axially for torque converters and fluid couplings asrequired in various installations and particularly in automotiveapplications. In many cases, it is desirable to dispose the fluidcoupling or torque converter in a limited diametrical space. Theconnections of the shells in accordance with the invention isparticularly practical in view of the fact that any of the connectionsrequire only a slight increase in diametrical space in some instances.This feature is advantageous where limited diametrical space would makeit impossible for housings of the bolted flange design to be utilized.

While this invention has been described in detail and in several formsor embodiments, it will be apparent to persons skilled in the art afterunderstanding the improvements, that various changes and modificationsmay be made therein in structure and methods of assembly withoutdeparting from the spirit of the scope thereof. It is therefore aimed inthe appended claims to cover all such changes and modifications.

I claim:

1. In a hydrodynamic coupling device, two opposed sheet metal shellshaving hollow portions defining a toroidal fluid-containing housing,said shells being provided with radially outer telescoping annularportions projecting in a common axial direction from the hollow portionof said shells, said opposed shells having a positive axial stop meanstherebetween and having circumferential edges adjacent each otherdisposed in a radial plane, seal means disposed between said shells, andcircumferentially spaced welds integral with said edges connecting saidshells to each other.

2. In a hydrodynamic coupling device, two opposed sheet metal shellshaving hollow portions defining a toroidal fluid-containing housing,said shells being provided with radially outer telescoping annularportions projecting in a common axial direction from the hollow portionsof said shells, said opposed shells having a positive axial stop meanstherebetween and circumferential edges adjacent each other disposed in aradial plane, seal means disposed between said shells, and a pluralityof circumferentially spaced means integral with said edges connectingsaid shells to each other.

3. In a hydrodynamic coupling device, two opposed sheet metal shellshaving hollow portions defining a toroidal fluid-containing housing,said shells being provided with radially outer telescoping annularportions projecting in a common axial direction from said hollowportions of said shells, said shells having a positive axial stop meanstherebetween and circumferential edges, one of said edges having aradially projecting edge overlapping the other of said edges tointerlock said shells together against axial separation, and seal meansdisposed between said shells.

4. An apparatus in accordance with claim 3 wherein said one of saidannular portions is provided with means cooperating with the other ofsaid annular portions to form a driving connection between said opposedshells.

Arnbrosius July 5, 1938 Cox et al Dec. 13, 1938 (Other references onfollowing page) 9 10 UNITED STATES PATENTS 2,651,918 Kelley et a1 Sept.15, 1953 2291797 DQ112611 Aug 4 942 2,657,307 Laundel' NOV. 19532,294,837 Dodge Sept. 1, 1942 2,658,692 Wolf 3 2,349,840 Babbitt May 30,1944 2,674,390 Meyer 6, 195 2,387,076 1011118011 Oct. 16, 1945 5 2750392Johnson June 19, 1956 2,432,790 OLarte eta] Dec, 16, 1947 2,784,675Farrell 12, 1957 2,439,630 Nutt Apr. 13, 1948 FOREIGN PATENTS 2,506,687Schcrrer M y 1950 2 4172 Switzerland Jul y 15, 1952 215871480 Gruetle1952 320,828 Great Britain Oct, 24, 1929 2,651,916 Batten Sept. 15, 195310

